Architecture and phenology of the Prosopis Juliflora and Acacia tortuosa in the semiarid area of Falcón state, Venezuela

The architecture and phenology of the species Prosopis juliflora (Pj) and Acacia tortuosa (At) was evaluated in a semiarid environment with temperature of 29 °C’s, evapotranspiration of 1708 mm, and rain fall of 540 mm, annual mean. A conglomerate of five mature individuals for species was selected, from a three ha exclusion area of natural forest. In each individual, it was measured the diameter, area of the cop, and the type and order of present branches. Also, fifteen productive branches were identified and evaluated to intervals of 34.7 ± 1.7d during one year. A total of 1560 observations of accumulated diameter (D) and length of the branch (L), number of buds (NDY), of leaves (NDH), and of buds with leaves (YCH) was subjected to an ANOVA using three statistical models and the "Proc GLM" of SAS. The effects specie: Si, i = 1, 2; individual within specie: I(S)ij, j = 1,. . . ,5 in both species; time: Tk, k = 1,. . ,11; order of branch: Ol, l = 1,. . .,6; branch: Rm, m = 1,. . .,15; and the interaction species x time: STik were common to all models. The Model for D included, in addition, the lineal effect of initial diameter; that of L the lineal effect of initial length, and the lineal and quadratic effect of D; and that of NDY, NDH, and YCH D and L lineal and quadratic as covariables. For D, L, and NDH, ST was not significant. The least square means for the given order variables are listed and for species were of 4.3 ± 0.04 vs 4.2 ± 0.04, 35.0 ± 0.7 vs 38.1 ± 0.6, 24.7 ± 0.4 vs 30.7 ± 0.4, 24.7 ± 0.4 vs 30.7 ± 0.4, 14.1 ± 0.4 vs 15.5 ± 0.4; and the density of one unit of NDY, NDH, and of YCH for each 1.5 vs 1.3, 1.4 vs 1.2, and 2.9 vs 2.2 cm’s length in Pj and At respectively. The increment in D was bigger in Pj, and the increase in L was of 9.05 ± 0.92 with a quadratic tendency of 0.31 ± 0.07 cm for each mm of increment in D, and it was bigger in At. Blooming of Pj reached top in the dry season, and that of the At at the beginning of the spring. The architecture was similar, in both species as for height, and diameter and area of the cop. Branches of order VII and IX were observed in Pj and At, respectively. The results are indicative that both species Pj and At have a complex architecture that is a characteristic of foragers arboreus species. However, the foliar components of DM seem to differ among them, with certain specie x season interaction. The Pj seems to have bigger activity during conditions of stress hydric, while the At responds better to moisture seasons

Localization Properties of the Periodic Random Anderson Model

We consider diagonal disordered one-dimensional Anderson models with an underlying periodicity. We assume the simplest periodicity, i.e., we have essentially two lattices, one that is composed of the random potentials and the other of non-random potentials. Due to the periodicity special resonance energies appear, which are related to the lattice constant of the non-random lattice. Further on two different types of behaviors are observed at the resonance energies. When a random site is surrounded by non-random sites, this model exhibits extended states at the resonance energies, whereas otherwise all states are localized with, however, an increase of the localization length at these resonance energies. We study these resonance energies and evaluate the localization length and the density of states around these energies.Comment: 4 page

Enhanced suppresion of localization in a continuous Random-Dimer Model

We consider a one-dimensional continuous (Kronig-Penney) extension of the (tight-binding) Random Dimer model of Dunlap et al. [Phys. Rev. Lett. 65, 88 (1990)]. We predict that the continuous model has infinitely many resonances (zeroes of the reflection coefficient) giving rise to extended states instead of the one resonance arising in the discrete version. We present exact, transfer-matrix numerical calculations supporting, both realizationwise and on the average, the conclusion that the model has a very large number of extended states.Comment: 10 pages, 3 Figures available on request, REVTeX 3.0, MA/UC3M/1/9

Discovery of the broad-lined Type Ic SN 2013cq associated with the very energetic GRB 130427A

Long-duration gamma-ray bursts (GRBs) at z < 1 are in most cases found to be accompanied by bright, broad-lined Type Ic supernovae (SNe Ic-BL). The highest-energy GRBs are mostly located at higher redshifts, where the associated SNe are hard to detect observationally. Here we present early and late observations of the optical counterpart of the very energetic GRB 130427A. Despite its moderate redshift z = 0.3399+/-0.0002, GRB 130427A is at the high end of the GRB energy distribution, with an isotropic-equivalent energy release of Eiso ~ 9.6x10^53 erg, more than an order of magnitude more energetic than other GRBs with spectroscopically confirmed SNe. In our dense photometric monitoring, we detect excess flux in the host-subtracted r-band light curve, consistent with what expected from an emerging SN, ~0.2 mag fainter than the prototypical SN 1998bw. A spectrum obtained around the time of the SN peak (16.7 days after the GRB) reveals broad undulations typical of SNe Ic-BL, confirming the presence of a SN, designated SN 2013cq. The spectral shape and early peak time are similar to those of the high expansion velocity SN 2010bh associated with GRB 100316D. Our findings demonstrate that high-energy long-duration GRBs, commonly detected at high redshift, can also be associated with SNe Ic-BL, pointing to a common progenitor mechanism.Comment: 12 pages, 4 figures, 1 table, accepted for publication in Ap

CALIFA, the Calar Alto Legacy Integral Field Area survey: I. Survey presentation

We present here the Calar Alto Legacy Integral Field Area (CALIFA) survey, which has been designed to provide a first step in this direction.We summarize the survey goals and design, including sample selection and observational strategy.We also showcase the data taken during the first observing runs (June/July 2010) and outline the reduction pipeline, quality control schemes and general characteristics of the reduced data. This survey is obtaining spatially resolved spectroscopic information of a diameter selected sample of $\sim600$ galaxies in the Local Universe (0.005< z <0.03). CALIFA has been designed to allow the building of two-dimensional maps of the following quantities: (a) stellar populations: ages and metallicities; (b) ionized gas: distribution, excitation mechanism and chemical abundances; and (c) kinematic properties: both from stellar and ionized gas components. CALIFA uses the PPAK Integral Field Unit (IFU), with a hexagonal field-of-view of \sim1.3\sq\arcmin', with a 100% covering factor by adopting a three-pointing dithering scheme. The optical wavelength range is covered from 3700 to 7000 {\AA}, using two overlapping setups (V500 and V1200), with different resolutions: R\sim850 and R\sim1650, respectively. CALIFA is a legacy survey, intended for the community. The reduced data will be released, once the quality has been guaranteed. The analyzed data fulfill the expectations of the original observing proposal, on the basis of a set of quality checks and exploratory analysis. We conclude from this first look at the data that CALIFA will be an important resource for archaeological studies of galaxies in the Local Universe.Comment: 32 pages, 29 figures, Accepted for publishing in Astronomy and Astrophysic

CALIFA : a diameter-selected sample for an integral field spectroscopy galaxy survey

JMA acknowledges support from the European Research Council Starting Grant (SEDmorph; P.I. V. Wild).We describe and discuss the selection procedure and statistical properties of the galaxy sample used by the Calar Alto Legacy Integral Field Area (CALIFA) survey, a public legacy survey of 600 galaxies using integral field spectroscopy. The CALIFA "mother sample" was selected from the Sloan Digital Sky Survey (SDSS) DR7 photometric catalogue to include all galaxies with an r-band isophotal major axis between 45 '' and 79 : 2 '' and with a redshift 0 : 005 M-r > -23 : 1 and over a stellar mass range between 10(9.7) and 10(11.4) M-circle dot. In particular, within these ranges, the diameter selection does not lead to any significant bias against - or in favour of - intrinsically large or small galaxies. Only below luminosities of M-r = -19 (or stellar masses <10(9.7) M-circle dot) is there a prevalence of galaxies with larger isophotal sizes, especially of nearly edge-on late-type galaxies, but such galaxies form <10% of the full sample. We estimate volume-corrected distribution functions in luminosities and sizes and show that these are statistically fully compatible with estimates from the full SDSS when accounting for large-scale structure. For full characterization of the sample, we also present a number of value-added quantities determined for the galaxies in the CALIFA sample. These include consistent multi-band photometry based on growth curve analyses; stellar masses; distances and quantities derived from these; morphological classifications; and an overview of available multi-wavelength photometric measurements. We also explore different ways of characterizing the environments of CALIFA galaxies, finding that the sample covers environmental conditions from the field to genuine clusters. We finally consider the expected incidence of active galactic nuclei among CALIFA galaxies given the existing pre-CALIFA data, finding that the final observed CALIFA sample will contain approximately 30 Sey2 galaxies.Peer reviewe

The Mass-Metallicity relation explored with CALIFA: I. Is there a dependence on the star formation rate?

We present the results on the study of the global and local M-Z relation based on the first data available from the CALIFA survey (150 galaxies). This survey provides integral field spectroscopy of the complete optical extent of each galaxy (up to 2-3 effective radii), with enough resolution to separate individual HII regions and/or aggregations. Nearly $\sim$3000 individual HII regions have been detected. The spectra cover the wavelength range between [OII]3727 and [SII]6731, with a sufficient signal-to-noise to derive the oxygen abundance and star-formation rate associated with each region. In addition, we have computed the integrated and spatially resolved stellar masses (and surface densities), based on SDSS photometric data. We explore the relations between the stellar mass, oxygen abundance and star-formation rate using this dataset. We derive a tight relation between the integrated stellar mass and the gas-phase abundance, with a dispersion smaller than the one already reported in the literature ($\sigma_{\Delta{\rm log(O/H)}}=$0.07 dex). Indeed, this dispersion is only slightly larger than the typical error derived for our oxygen abundances. However, we do not find any secondary relation with the star-formation rate, other than the one induced due to the primary relation of this quantity with the stellar mass. We confirm the result using the $\sim$3000 individual HII regions, for the corresponding local relations. Our results agree with the scenario in which gas recycling in galaxies, both locally and globally, is much faster than other typical timescales, like that of gas accretion by inflow and/or metal loss due to outflows. In essence, late-type/disk dominated galaxies seem to be in a quasi-steady situation, with a behavior similar to the one expected from an instantaneous recycling/closed-box model.Comment: 19 Pages, 8 figures, Accepted for Publishing in Astronomy and Astrophysics (A&A

Mechanical behavior of asphalt mixtures containing silica gels as warm additives

This paper presents the results of a study of some compounds capable of absorbing water into their structure (silica gel), as potential foaming binders. Asphalt mixtures were manufactured at different manufacturing and compaction temperatures, using four different silica gels. Static and dynamic tests were carried out to determine their behavior in asphalt mixtures. The results were compared with those obtained using hot-mix asphalt and warm-mix asphalt manufactured with zeolite. The lab results showed a similar behavior of asphalt mixtures containing either silica gel or zeolite.The research presented herein was sponsored by the Research Office of Universidad de La Frontera (DIUFRO) under the project number DI15-0089